I have two SATA HDDs full of data. I was running my OS off of a SATA SSD (Crucial MX100) and just switched over to a Samsung 950 Pro which is M.2. I installed the 950 Pro and upon boot up none of the SATA drives are recognizing at all. Not even the DVD drive. I have windows installed and working fine on the 950 Pro but still no SATA drive access. I've also fiddled a ton in the BIOS settings but I assume it's possible I missed something obvious. Any ideas?